本文選題：無鐘高爐　切入點：爐料運動　出處：《北京科技大學》2017年博士論文　論文類型：學位論文

【摘要】：當前,在鋼鐵工業(yè)節(jié)能減排和制造業(yè)升級背景下,要求實現(xiàn)高爐高效低碳冶煉以及精細化操作控制,優(yōu)化改善高爐操作成為重點之一。上部裝料制度作為高爐四大操作制度中最靈活和最常用的調(diào)劑手段,決定著爐內(nèi)的爐料顆粒分布狀況,進而影響爐內(nèi)煤氣流分布,對促進高爐順行、提高煤氣利用率、降低燃料比等有著重要作用。目前廣泛使用的高爐無鐘爐頂主要分為串罐式爐頂和并罐式爐頂,兩者裝料規(guī)律差異巨大,并罐式爐頂裝料過程爐料運動分布規(guī)律更加復雜,且已有研究尚存不足；另一方面,高爐裝料過程中爐料既以宏觀整體料流形態(tài)運動分布,又存在著微觀上不同粒徑和不同種類顆粒間偏析分布,而長期以來對后者研究認識不足。因此,在前人研究工作基礎(chǔ)上,本文針對串罐式和并罐式無鐘高爐裝料過程分別運用機理建模方法和離散元仿真方法對爐料宏觀運動分布規(guī)律和微觀顆粒偏析行為進行了系統(tǒng)的研究分析,為后續(xù)高爐爐頂設(shè)計選型及生產(chǎn)操作實踐提供了參考依據(jù)和理論指導。主要研究內(nèi)容及結(jié)果如下：(1)考慮到串、并罐無鐘爐頂以及不同型式溜槽布料差異性,通過分析爐料運動受力狀況,建立了節(jié)流閥出口處爐料流速數(shù)學模型、節(jié)流閥至溜槽間爐料運動數(shù)學模型、多環(huán)布料過程中半圓形截面溜槽和矩形截面溜槽內(nèi)爐料運動三維數(shù)學模型、空區(qū)內(nèi)料流軌跡及料流寬度數(shù)學模型、爐料落點及瞬時流量數(shù)學模型和料面形狀數(shù)學模型,并通過1：7布料模型實驗驗證了所建立數(shù)學模型的準確性與可靠性。其中,首次針對并罐式爐頂常用的弧形閘板,閥建立其排料時爐料流速數(shù)學模型,定量計算出并罐布料時爐料分別在半圓形截面溜槽和矩形截面溜槽內(nèi)的落點軌跡形狀,指出前者為非橢圓狀、后者為橢圓形,同時考慮了多環(huán)布料時溜槽水平圓周旋轉(zhuǎn)和傾動的復合運動特點,可計算環(huán)形布料和螺旋布料工況。(2)利用本文開發(fā)的布料綜合數(shù)學模型分別計算分析了爐頂設(shè)備結(jié)構(gòu)參數(shù)和高爐生產(chǎn)相關(guān)參數(shù)兩類主要影響因素對爐料運動分布影響,前者主要包括無鐘爐頂型式、中心喉管內(nèi)徑、溜槽懸掛點高度、溜槽傾動距、溜槽長度、溜槽截面形狀等,后者則主要包括爐料種類、并罐“倒罐”模式、節(jié)流閥開度、溜槽傾角、溜槽轉(zhuǎn)速、溜槽轉(zhuǎn)向、料線高度、煤氣流速等。結(jié)果表明：并罐式高爐布料時同時存在料面爐料落點和瞬時流量圓周偏析；溜槽懸掛點高度、溜槽傾動距、溜槽長度、溜槽傾角和料線高度主要影響爐料落點遠近,對并罐布料爐料落點和流量圓周偏析程度影響較�。粶p小中心喉管內(nèi)徑和增大節(jié)流閥開度均能有效降低并罐布料爐料落點和流量圓周偏析程度；相比半圓形截面溜槽,矩形截面溜槽對應(yīng)的料流寬度較小、料流更加集中,在料面上的落點半徑和流量圓周偏析程度也更低；溜槽轉(zhuǎn)速或煤氣流速增大不僅使爐料落點半徑整體增大,還將加重并罐布料流量偏析；并罐布料時改變“倒罐”模式和溜槽轉(zhuǎn)向?qū)⑹範t料落點和流量圓周分布曲線分別與原曲線關(guān)于高爐中心和0°-180°線對稱分布,因此能夠在一定程度上彌補爐內(nèi)偏析程度。(3)基于離散單元法建立了離散爐料顆粒運動數(shù)學模型,分別針對實際4350m3串罐式無鐘高爐和5500m3并罐式無鐘高爐從料倉至爐喉的整個裝料過程進行了仿真研究,分析了各環(huán)節(jié)內(nèi)微觀顆粒偏析行為,并利用串罐高爐開爐實測結(jié)果驗證了仿真模型的可靠性。研究發(fā)現(xiàn),爐料顆粒間偏析分布現(xiàn)象貫穿于整個裝料過程中,在皮帶料層厚度方向存在大小顆粒偏析分布,在串罐式爐頂?shù)纳稀⑾铝瞎藓筒⒐奘綘t頂?shù)淖�、右料罐�?nèi)顆粒分布也不均勻;料罐排料時,罐內(nèi)爐料呈“漏斗流”,排料前期顆粒平均粒徑較小、后期較大,末期則有較多小顆粒排出,導料錐存在能夠減小串罐排料時顆粒粒度變化幅度；爐料顆粒在溜槽內(nèi)會發(fā)生偏轉(zhuǎn),對于并罐式高爐布料,溜槽位于不同方位時其內(nèi)部顆粒運動狀況不同；在爐喉內(nèi),主要是徑向和縱向上顆粒平均粒徑變化較大,周向偏析較小,但并罐式高爐裝料時,爐喉周向還存在爐料體積分布不均現(xiàn)象。
[Abstract]:At present, the upgrade background in iron and steel industry energy-saving emission reduction and manufacturing, to achieve high efficiency and low carbon requirements of blast furnace smelting and fine operation control, optimization and improvement of blast furnace operation has become the focus of one of the top charging system of blast furnace. As the four operating system is the most flexible and most commonly used means of regulating agent, determines the distribution of charge particles in furnace then, effect of gas flow distribution in the furnace, to promote the smooth operation of blast furnace, improve the utilization rate of gas, reducing fuel ratio plays an important role. The widely used blast furnace bell less top is divided into series tank top and a tank top and two charging rules, huge, and tank top charging process of charge movement distribution is more complex, and the existing research still insufficient; on the other hand, in the process of charging of blast furnace burden both to the overall flow of movement patterns and the presence of the microscopic distribution of different particle size and With the segregation of species distribution between particles, and for a long time to the study of lack of knowledge. Therefore, based on the previous research work, this paper on the tank and tank bell charging process using mechanism modeling method and discrete element method of system simulation research has carried on the analysis to the macro and micro motion charge distribution particle segregation behavior, provide reference and theoretical guidance for the subsequent blast furnace design selection and production practice. The main research contents and results are as follows: (1) taking into account the string, and bell furnace top and different types of distribution chute differences, through the analysis of charge movement stress condition, established the outlet throttle valve charge flow mathematical model, the throttle valve to the chute between charge movement mathematical model, a three-dimensional mathematical charge movement semi circular section and rectangular section chute chute ring charging model, The empty area material flow and material flow path width model, charge placement and instantaneous flow mathematical model and mathematical model of surface shape, and the accuracy and reliability of the mathematical model is verified by experiments. The 1:7 distribution model for the first time, the arc gate and the tank top is used, the discharge valve is established when the charge flow mathematical model, quantitative calculation and cloth respectively in charge tank semi circular section and rectangular section chute chute of the landing trajectory shape, pointed out that the former is non elliptical, the latter is oval, considering the rotation and tilting chute horizontal circumferential motion characteristics of polycyclic composite cloth and cloth cloth can be calculated ring and spiral case. (2) using a comprehensive mathematical model of cloth is developed in this paper to calculate the factors of structural parameters and blast furnace top equipment production related parameters of two kinds of effect on furnace material transport The dynamic distribution of influence, the former mainly includes the type of bell less top, center pipe diameter, the suspension height chute, chute tilting distance, the length of the chute, chute cross-section shape, the latter mainly includes the furnace type, and tank "tank" mode, the throttle valve opening, chute, chute, chute feed speed, steering, line height, gas velocity. The results show that the tank and the blast furnace burden when exist at the same time charge placement and instantaneous flow circumferential segregation; the suspension height chute, chute tilting distance, the length of the chute, chute and feed line height mainly affected placement distance has little effect on the charge, and can charge cloth placement and flow circle segregation the center pipe diameter and increase; reduce the throttle valve opening can effectively reduce the burden of cloth and tank placement and traffic circle segregation; compared with semi circular section chute, rectangular chute corresponding stream width 搴﹁緝?yōu)?

本文編號：1612968